If it were me, I'd either get the upgrade done, just as the others have said. It provides your whole house with MUCH better saftey. I also would spend the extra 70 bucks and run a seperate circuit to where your tank is going to be, and also put arc fault breakers in the panel. I just hope your house has either attic access or a crawl-space access...

Btw... I'm in the process of going through certification classes for home inspecting here in GA... It sounds like there are a couple of other qualified ppl here as well...

If you're spending 2000 + on a tank, spend less than that to get your entire house upgraded, IMO.